Carburetor



April 12, 1966 M. .1. KITTLER ET AL 3,245,657

,47m/ave y United States Patent O 3,245,667 CARBUREIOR Milton J. Kittler and Melvin F. Sterner, Bloomfield Hills,

and Marion L. Smitley, Huntington Woods, Mich., assignors to Holley Carburetor Company, Warren, Mich.,

a corporation of Michigan Filed Dec. 26, 1962, Ser. No. 247,604 2 Claims. (Cl. 261-69) the carburetor, they may at times become heated to the extent that fuel passing therethrough is partially vaporized resulting in erratic metering.

Accordingly, an object of this invention is provide a fuel metering system that is less prone to vapor problems by reason of the metering jet structure thereof being cornpletely immersed in the reservoir fuel.

- Another object of the invention is to provide a single carburetor metering unit, the operation of which provides a result equivalent to the normal operation of the usual separate main and power enrichment systems.

A further object of this invention is to provide a fuel metering unit constructed in such a way as to be easily and quickly removable for cleaning or replacement purposes, without having to disassemble any other portion of the carburetor, thereby considerably reducing maintenance costs.

Other more specific objects and advantages of the invention will become apparent when reference is made to vthe following description and the accompanying illustrations wherein:

FIGURE 1 is a fragmentary cross-sectional view of a two-barrel carburetor embodying the invention, taken on a plane passing through the axes of the induction passages;

FIGURE 2 is a fragmentary cross-sectional view of the `same carburetor on a plane passing between the induction passages at right angles to the plane of FIGURE l.

FIGURE 3 is a fragmentary cross-sectional view taken on the plane of line 3-3 of FIGURE 2, and looking in the direction of the arrows.

Referring to the drawings in greater detail, FIGURE l illustrates a two-barrel carburetor mounted on an engine intake manifold 12. It is to be understood, however, that the invention may be employed in any carburetor requiring the conventional main and power enrichment fuel systems, or the equivalent thereof.

The carburetor 10 contains the usual induction passages 14, each passage having a main fuel nozzle 18 including a booster venturi 19, which is not used in all cases, a main venturi 20 and a throttle plate 22. The combination main and power enrichment fuel metering system 24 may be supplied with fuel by `any suitable fuel reservoir chamber 26 formed in the carburetor. In the case of the two-barrel carburetor shown, it is preferable, of course, that the reservoir 26 be positioned approximately between the induction passages 14.

The system 24 shown includes a generally cylindrical body 28 having external threads 25 so that it may be assembled into a bridge portion 29 extending between the spaced passages 14 of the carburetor, with the lower porice tion of body 28 extending into the reservoir 26. The body 28 includes one or more outlet ports 30 extending from a central passageway 32 sealed at one end by a plug 42 and formed to provide -a calibrated restriction 34, a valve seat 36 and a larger cylindrical chamber 38 at the other end thereof. The body 28 may also include a flange 40 adapted to engage a suitable seal 44 positioned between the flange 40 and the bridge portion 29 to prevent leakage past the external threads 2S of the body 28. An O ring seal 46 positioned in a groove 48 formed in the body 28 may be used to insure that no fuel can flow around the body 28. If required for any reason, the cylindrical body 28 may be adjusted vertically by shims or other convenient means.

A triangular or square. valve member Si) (see FIG- URE 3) containing a central passageway 52, which includes a smaller calibrated restriction 54, is slidably inserted into the chamber 3S of the body 28 and retained therein by any suitable means such as a retaining ring 56. A portion 5S of the valve 5t) extends beyond the end of the body 28 and includes one or more inlet ports 60 formed through the walls thereof. The annular chamber 59 and the conduits 62 formed in the bridge portion 29 extending over reservoir 26 communicate between the outlet ports 30 andthe main fuel nozzles 18.

A pivotable lever 64, better seen in FIGURE 2, is located below the valve portion SS by means of a pivot pin 66 extending between two bosses 68. The end 70 of the lever 64 contacts the extension 58, while the other forked end 72 is pivotally connected to the diaphragm 74 by means of a stud 76 and pin 78, the stud 76 extending through an opening S2 in the bottom of the reservoir 26 and being connected to the diaphragm by the conventional washers 84 positioned on both sides of the diaphragm 72. The diaphragm 74 is clamped at its outer edges between the outer wall of the reservoir 26 and a separate diaphragm housing 86 so as to form chambers 88 and 90 having the diaphragm as a common wall. The diaphragm housing 86 may be attached to reservoir 26 wall by any suitable means such as screws 94, and the diaphragm 74 is urged upwardly or toward the reservoir 26 wall by a suitable resilient means such as the spring 92. Any suitable conduit 96 is provided to communicate vacuum from the engine intake manifold 12 to the spring chamber 9).

Operation As is vwell known in the art, air drawn into the induction passage 14 by the operation of the engine creates a vacuum at the venturi 20 and at the main nozzle 18, which in this case includes a so-called booster venturi 19. The pressure differential between the positive pressure above the fuel in the fuel reservoir 26 land the vacuum at the main nozzle 1S causes a metered flow of fuel from the fuel reservoir 26 into the induction passage 14, via the connecting passageways. As stated above, the present practice is to provide independent main and power enrichment fuel metering systems, the former functioning at all engine speeds above idle and the latter functioning additively only at high speed or heavy load conditions.

As will be seen in the discussion which follows, the invention contemplates cooperating main and power enrichment systems integrated into a single system capable of providing two different metering characteristics that are, in effect, operative alternately at predetermined times. That is, the combined system employs separate main and power metering restrictions, only one of which is controlling at any given condition of engine operation.

During part throttle operating conditions, when a high manifold vacuum is being supplied to the chamber in the diaphragm housing S6 via the conduit 96, the diaphragm 74 is caused to overcome the spring 92 and move away from the wall of the reservoir 26. This pulls the attached stud '76 downwardly, pivoting the end 7i) of actuating lever 6ft upwardly in FIGURE 2 so as to raise the valve Si) against the seat 36. In this closed condition of valve Sil, fuel is caused to flow from the reservoir 26 into the induction passage M via the inlet ports 60, passage 52, controlling `restriction S4, ineffective restriction 34, outlet ports 30 and the conduits 62 leading to the main fuel nozzles 1S. In other words, it can be seen that the effective metering restriction during this period of high manifold vacuum is the smaller restriction 54, which is calibrated for proper fuel dow at all part throttle engine operating conditions not requiring the extra power fuel.

During high speed or heavy load conditions, when the manifold vacuum transmitted to the diaphragm chamber 9i) via the conduit 96 drops to some predetermined lower value, the diaphragm 74 is moved toward the wall of the Vfuel reserv-oir 26 by the calibrated spring 92, thereby pivoting the end '70 of the actuating lever 64 downwardly in FIGURE 2 and allowing t-he valve 50 to drop .away from the seat 36. In this open condition of valve 50, fuel in addition to that which enters the passageway 52 Vthrough the inlet ports 60 can ow npwarly through the clearance between the square or triangular valve Sil and the wall of the chamber 38, past the seat 36 and thence through theV larger calibrated restriction 34', the outlet'V ports 30, and the conduits 62 to the induction passage 14. It can thus be seen that during this lower manifold vacuum wide-open-throttle ycondition of engine operation, the larger restriction 34 is the effective metering determinant, and the resultant rich mixture lwhich is required for high speed or heavy load conditions is controlled by the calibrated size of this larger restriction 34; That is, the smaller restriction 54 may flow some Ifuel, but it does not control metering during this phase of engine operation.

From the above, it should be apparent that the invention embodies a unique and compact single system for efficiently and automatically supplying the fuel required under all olf-idle engine operating conditions by alternately giving effect, in a common passageway, to a smaller or a larger calibrated restriction as the controlling fuel meter- .f

ing medium.

It should be further apparent that the sub-assembly embodying this fuel system may be readily removed from the carburetor, for most cleaning or replacement purposes, without having to disassemble any part of the main carburetor body.

Also, it should be still further apparent that the possibilities of erratic metering due to fuel becoming vaporized,

- as a result of its having to flow through a heated metering jet, will be considerably decreased in a system embodying the invention by virtue of the metering jet being locatedv a substantial distance away from the carburetor wall and completely surrounded by fuel in the reservoir.

While only one embodiment of the inventionrhas been illustrated and described, it is conceivable that other modifications are possible within the scope of the appended claims.

What we claim as our invention is:

1. ln an internal combustion engine carburetor having an induction passage with a fuel nozzle positioned in a venturi restriction, a fuel reservoir and a fuel passage leading from said fuel reservoir to said fuel nozzle, :a fuel metering device insertable into saidpassage from the outside of said carburetor upstream of said nozzle, said device comprising a body formed to provide an axial passage containing a larger xed restriction for metering fuel at lower engine vacuums and a movable valve element, said movable valve element being formed to provide a smaller restriction aligned axially ywith said fixed restriction for metering fuel required at higher engine vacuums, means for inserting said'device into said passage as a unit without disturbing any other portion of said carburetor and such that the inner end thereof extends into and is completely surrounded by the fuel in said reservoir, and engine manifold vacuum responsive means for positioning said valve so as to determine which restriction controls metering o-f the fuel.

2. In an internal combustion engine carburetor having a fuel reservoir and an induction passage including a venturi and a fuel nozzle therein, a system for metering the fuel drawn to said fuel nozzle-by venturi vacuum, said system comprising a body ixedly attachedY to said carburetor and'extendinginto said reservoir;r said -body including an outlet port, la valve seat and a first axial pas'- sageway having a first restriction and a chamber therein; a pistonslidably' mounted in said chambensaid piston including an inlet'port and a second axial Ipassageway having a second restriction therein, said second axial passageway being in alignment with said rst axial passageway; and a vacuum responsive device for moving said piston in said chamber so as to at times. seat said piston against said valve seat, said vacuum responsive device including an externally mounted housing, a diaphragm forming two chambers mounted in said housing, a stud xedly attached to said diaphragm and extending into said reservoir, a lever pivotally attached intermediate its ends to said carburetonsaid lever having its one end pivotally attached to said stud and its other end in contact with said piston, resilient means in one of said chambers for urging said diaphragm and said stud in a direction so as to permit said piston to leave said valve seat, and a conduit communicating engine vacuum to said chamber containing said resilient means.

References Cited bythe Examiner f UNITED STATES lPATENT S 1,869,122 7/1932 Vincent.

2,311,827 2/1943 Hansen.

2,694,561) 11/1954 Olson 261-69 2,757,913 8/1956 Sutton et a1.

2,831,471 4/1958 Schoonover 261-69 2,977,948 4/ 1961 Kittler 261-69 3,013,777 12/1961 White 261-69 HARRY B. THORNTON, Primary Examiner.

RONALD R. WEAVER, Examiner. 

1. IN AN INTERNAL COMBUSTION ENGINE CARBURETOR HAVING AN INDUCTION PASSAGE WITH A FUEL NOZZLE POSITIONED IN A VENTURI RESTRICTION, A FUEL RESERVOIR AND A FUEL PASSAGE LEADING FROM SAID FUEL RESERVOIR TO SAID FUEL NOZZLE, A FUEL METERING DEVICE INSERTABLE INTO SAID PASSAGE FROM THE OUTSIDE OF SAID CARBURETOR UPSTREAM OF SAID NOZZLE, SAID DEVICE COMPRISING A BODY FORMED TO PROVIDE AN AXIAL PASSAGE CONTAINING A LARGER FIXED RESTRICTION FOR MATERING FUEL AT LOWER ENGINE VACUUMS AND A MOVABLE VALVE ELEMENT, SAID MOVABLE VALVE ELEMENT BEING FORMED TO PROVIDE A SMALLER RESTRICATION ALIGNED AXIALLY WITH SAID FIEXED RESTIRCTION FOR METERING FUEL REQUIRED AT HIGHER ENGINE VACUUMS, MEANS FOR INSERTING SAID DEVICE INTO SAID PASSAGE AS A UNIT WITHOUT DISTURBING ANY OTHER PORTION OF SAID CARBURETOR AND SUCH THAT THE INNER END THEREOF EXTENDS INTO AND IS COMPLETELY SURROUNDED BY THE FUEL IN SAID RESERVOIR, AND ENGINE MANIFOLD VACUUM RESPONSIVE MEANS FOR POSITIONING SAID VALVE SO AS TO DETERMINE WHICH RESTRICTION CONTROLS METERING OF THE FUEL. 